/*
 * Copyright (c) 2001-2003 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 */
#ifndef __LWIP_TCP_H__
#define __LWIP_TCP_H__

#include "lwip/sys.h"
#include "lwip/mem.h"

#include "lwip/pbuf.h"
#include "lwip/opt.h"
#include "lwip/ip.h"
#include "lwip/icmp.h"

#include "lwip/sys.h"

#include "lwip/err.h"

struct tcp_pcb;

/* Functions for interfacing with TCP: */

/* Lower layer interface to TCP: */
void tcp_init(void); /* Must be called first to
           initialize TCP. */
void tcp_tmr(void);  /* Must be called every
           TCP_TMR_INTERVAL
           ms. (Typically 250 ms). */
/* Application program's interface: */
#define tcp_new() tcp_alloc(TCP_PRIO_NORMAL);

struct tcp_pcb *tcp_alloc(u8_t prio);

#define tcp_arg(pcb, arg) pcb->callback_arg = (arg)

void tcp_accept(struct tcp_pcb *pcb,
                err_t (*accept)(void *arg, struct tcp_pcb *newpcb,
                                err_t err));
void tcp_recv(struct tcp_pcb *pcb,
              err_t (*recv)(void *arg, struct tcp_pcb *tpcb,
                            struct pbuf *p, err_t err));
void tcp_sent(struct tcp_pcb *pcb,
              err_t (*sent)(void *arg, struct tcp_pcb *tpcb,
                            u16_t len));
void tcp_poll(struct tcp_pcb *pcb,
              err_t (*poll)(void *arg, struct tcp_pcb *tpcb),
              u8_t interval);
void tcp_err(struct tcp_pcb *pcb,
             void (*err)(void *arg, err_t err));

#define tcp_mss(pcb)    ((pcb)->mss)
#define tcp_sndbuf(pcb) ((pcb)->snd_buf)

void tcp_recved(struct tcp_pcb *pcb, u16_t len);
err_t tcp_bind(struct tcp_pcb *pcb, struct ip_addr *ipaddr,
               u16_t port);
err_t tcp_connect(struct tcp_pcb *pcb, struct ip_addr *ipaddr,
                  u16_t port, err_t (*connected)(void *arg, struct tcp_pcb *tpcb, err_t err));
struct tcp_pcb *tcp_listen(struct tcp_pcb *pcb);
void tcp_abort(struct tcp_pcb *pcb);
err_t tcp_close(struct tcp_pcb *pcb);
err_t tcp_write(struct tcp_pcb *pcb, const void *dataptr, u16_t len,
                u8_t copy);

#define tcp_setprio(pcb, prio) pcb->prio = (prio)

#define TCP_PRIO_MIN    1
#define TCP_PRIO_NORMAL 64
#define TCP_PRIO_MAX    127

/* It is also possible to call these two functions at the right
   intervals (instead of calling tcp_tmr()). */
void tcp_slowtmr(void);
void tcp_fasttmr(void);


/* Only used by IP to pass a TCP segment to TCP: */
void tcp_input(struct pbuf *p, struct netif *inp);
/* Used within the TCP code only: */
err_t tcp_output(struct tcp_pcb *pcb);
void tcp_rexmit(struct tcp_pcb *pcb);



#define TCP_SEQ_LT(a, b)  ((s32_t)((a) - (b)) < 0)
#define TCP_SEQ_LEQ(a, b) ((s32_t)((a) - (b)) <= 0)
#define TCP_SEQ_GT(a, b)  ((s32_t)((a) - (b)) > 0)
#define TCP_SEQ_GEQ(a, b) ((s32_t)((a) - (b)) >= 0)

#define TCP_FIN 0x01U
#define TCP_SYN 0x02U
#define TCP_RST 0x04U
#define TCP_PSH 0x08U
#define TCP_ACK 0x10U
#define TCP_URG 0x20U
#define TCP_ECE 0x40U
#define TCP_CWR 0x80U

#define TCP_FLAGS 0x3fU

/* Length of the TCP header, excluding options. */
#define TCP_HLEN 20

#ifndef TCP_TMR_INTERVAL
#define TCP_TMR_INTERVAL 160 /* The TCP timer interval in \
                                milliseconds. */
#endif                       /* TCP_TMR_INTERVAL */

#ifndef TCP_FAST_INTERVAL
#define TCP_FAST_INTERVAL TCP_TMR_INTERVAL /* the fine grained timeout in \
                                  milliseconds */
#endif                                     /* TCP_FAST_INTERVAL */

#ifndef TCP_SLOW_INTERVAL
#define TCP_SLOW_INTERVAL (2 * TCP_TMR_INTERVAL) /* the coarse grained timeout in \
                                   milliseconds */
#endif                                           /* TCP_SLOW_INTERVAL */

#define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */
#define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */

#define TCP_OOSEQ_TIMEOUT 6 /* x RTO */

#define TCP_MSL 60000 /* The maximum segment lifetime in microseconds */

/*
 * User-settable options (used with setsockopt, IPPROTO_TCP level).
 */
#define TCP_NODELAY    0x01 /* don't delay send to coalesce packets */
#define TCP_KEEPALIVE  0x02 /* send KEEPALIVE probes when idle for pcb->keepalive miliseconds */
#define TCP_ACKNODELAY 0x04 /* send ack as soon as data is received [not standard] */
#define TCP_EVENSEG    0x08 /* Boman666 patch: send an even number of segments [not standard] */

/* Keepalive values */
#define TCP_KEEPDEFAULT 7200000                    /* KEEPALIVE timer in miliseconds */
#define TCP_KEEPINTVL   75000                      /* Time between KEEPALIVE probes in miliseconds */
#define TCP_KEEPCNT     9                          /* Counter for KEEPALIVE probes */
#define TCP_MAXIDLE     TCP_KEEPCNT *TCP_KEEPINTVL /* Maximum KEEPALIVE probe time */


#ifdef PACK_STRUCT_USE_INCLUDES
#include "arch/bpstruct.h"
#endif
PACK_STRUCT_BEGIN
struct tcp_hdr
{
    PACK_STRUCT_FIELD(u16_t src);
    PACK_STRUCT_FIELD(u16_t dest);
    PACK_STRUCT_FIELD(u32_t seqno);
    PACK_STRUCT_FIELD(u32_t ackno);
    PACK_STRUCT_FIELD(u16_t _hdrlen_rsvd_flags);
    PACK_STRUCT_FIELD(u16_t wnd);
    PACK_STRUCT_FIELD(u16_t chksum);
    PACK_STRUCT_FIELD(u16_t urgp);
} PACK_STRUCT_STRUCT;
PACK_STRUCT_END
#ifdef PACK_STRUCT_USE_INCLUDES
#include "arch/epstruct.h"
#endif

#define TCPH_OFFSET(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 8)
#define TCPH_HDRLEN(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 12)
#define TCPH_FLAGS(phdr)  (ntohs((phdr)->_hdrlen_rsvd_flags) & TCP_FLAGS)

#define TCPH_OFFSET_SET(phdr, offset) (phdr)->_hdrlen_rsvd_flags = htons(((offset) << 8) | TCPH_FLAGS(phdr))
#define TCPH_HDRLEN_SET(phdr, len)    (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | TCPH_FLAGS(phdr))
#define TCPH_FLAGS_SET(phdr, flags)   (phdr)->_hdrlen_rsvd_flags = htons((ntohs((phdr)->_hdrlen_rsvd_flags) & ~TCP_FLAGS) | (flags))
#define TCPH_SET_FLAG(phdr, flags)    (phdr)->_hdrlen_rsvd_flags = htons(ntohs((phdr)->_hdrlen_rsvd_flags) | (flags))
#define TCPH_UNSET_FLAG(phdr, flags)  (phdr)->_hdrlen_rsvd_flags = htons(ntohs((phdr)->_hdrlen_rsvd_flags) | (TCPH_FLAGS(phdr) & ~(flags)))

#define TCP_TCPLEN(seg) ((seg)->len + ((TCPH_FLAGS((seg)->tcphdr) & TCP_FIN || \
                                        TCPH_FLAGS((seg)->tcphdr) & TCP_SYN) ? \
                                           1 :                                 \
                                           0))

enum tcp_state {
    CLOSED = 0,
    LISTEN = 1,
    SYN_SENT = 2,
    SYN_RCVD = 3,
    ESTABLISHED = 4,
    FIN_WAIT_1 = 5,
    FIN_WAIT_2 = 6,
    CLOSE_WAIT = 7,
    CLOSING = 8,
    LAST_ACK = 9,
    TIME_WAIT = 10
};


/* the TCP protocol control block */
struct tcp_pcb
{
    /* Common members of all PCB types */
    IP_PCB;

    /* Protocol specific PCB members */

    struct tcp_pcb *next; /* for the linked list */

    enum tcp_state state; /* TCP state */

    u8_t prio;
    void *callback_arg;

    u16_t local_port;
    u16_t remote_port;

/* spooo : need more than 8 bits because of TF_ACKNODELAY and TF_EVENSEG
  u8_t flags; */
#define flags_t /*u8_t*/ u16_t
    flags_t flags;
#define TF_ACK_DELAY  (flags_t)0x01U  /* Delayed ACK. */
#define TF_ACK_NOW    (flags_t)0x02U  /* Immediate ACK. */
#define TF_INFR       (flags_t)0x04U  /* In fast recovery. */
#define TF_RESET      (flags_t)0x08U  /* Connection was reset. */
#define TF_CLOSED     (flags_t)0x10U  /* Connection was sucessfully closed. */
#define TF_GOT_FIN    (flags_t)0x20U  /* Connection was closed by the remote end. */
#define TF_NODELAY    (flags_t)0x40U  /* Disable Nagle algorithm */
#define TF_ACKNODELAY (flags_t)0x80U  /* Force ACK at every receive [not standard] */
#define TF_EVENSEG    (flags_t)0x100U /* Send an even number of segment [not standard] */

    /* receiver varables */
    u32_t rcv_nxt; /* next seqno expected */
    u16_t rcv_wnd; /* receiver window */

    /* Timers */
    u32_t tmr;
    u8_t polltmr, pollinterval;

    /* Retransmission timer. */
    u16_t rtime;

    u16_t mss; /* maximum segment size */

    /* RTT estimation variables. */
    u16_t rttest; /* RTT estimate in 500ms ticks */
    u32_t rtseq;  /* sequence number being timed */
    s16_t sa, sv;

    u16_t rto; /* retransmission time-out */
    u8_t nrtx; /* number of retransmissions */

    /* fast retransmit/recovery */
    u32_t lastack; /* Highest acknowledged seqno. */
    u8_t dupacks;

    /* congestion avoidance/control variables */
    u16_t cwnd;
    u16_t ssthresh;

    /* sender variables */
    u32_t snd_nxt,        /* next seqno to be sent */
        snd_max,          /* Highest seqno sent. */
        snd_wnd,          /* sender window */
        snd_wl1, snd_wl2, /* Sequence and acknowledgement numbers of last
       window update. */
        snd_lbb;          /* Sequence number of next byte to be buffered. */

    u16_t acked;

    u16_t snd_buf;     /* Available buffer space for sending (in bytes). */
    u8_t snd_queuelen; /* Available buffer space for sending (in tcp_segs). */


    /* These are ordered by sequence number: */
    struct tcp_seg *unsent;  /* Unsent (queued) segments. */
    struct tcp_seg *unacked; /* Sent but unacknowledged segments. */
#if TCP_QUEUE_OOSEQ
    struct tcp_seg *ooseq; /* Received out of sequence segments. */
#endif                     /* TCP_QUEUE_OOSEQ */

#if LWIP_CALLBACK_API
    /* Function to be called when more send buffer space is available. */
    err_t (*sent)(void *arg, struct tcp_pcb *pcb, u16_t space);

    /* Function to be called when (in-sequence) data has arrived. */
    err_t (*recv)(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);

    /* Function to be called when a connection has been set up. */
    err_t (*connected)(void *arg, struct tcp_pcb *pcb, err_t err);

    /* Function to call when a listener has been connected. */
    err_t (*accept)(void *arg, struct tcp_pcb *newpcb, err_t err);

    /* Function which is called periodically. */
    err_t (*poll)(void *arg, struct tcp_pcb *pcb);

    /* Function to be called whenever a fatal error occurs. */
    void (*errf)(void *arg, err_t err);
#endif /* LWIP_CALLBACK_API */

    /* idle time before KEEPALIVE is sent */
    u32_t keepalive;

    /* KEEPALIVE counter */
    u8_t keep_cnt;
};

struct tcp_pcb_listen
{
    /* Common members of all PCB types */
    IP_PCB;

    /* Protocol specific PCB members */
    struct tcp_pcb_listen *next; /* for the linked list */

    /* Even if state is obviously LISTEN this is here for
     * field compatibility with tpc_pcb to which it is cast sometimes
     * Until a cleaner solution emerges this is here.FIXME
     */
    enum tcp_state state; /* TCP state */

    u8_t prio;
    void *callback_arg;

    u16_t local_port;

#if LWIP_CALLBACK_API
    /* Function to call when a listener has been connected. */
    err_t (*accept)(void *arg, struct tcp_pcb *newpcb, err_t err);
#endif /* LWIP_CALLBACK_API */
};

#if LWIP_EVENT_API

enum lwip_event {
    LWIP_EVENT_ACCEPT,
    LWIP_EVENT_SENT,
    LWIP_EVENT_RECV,
    LWIP_EVENT_CONNECTED,
    LWIP_EVENT_POLL,
    LWIP_EVENT_ERR
};

err_t lwip_tcp_event(void *arg, struct tcp_pcb *pcb,
                     enum lwip_event,
                     struct pbuf *p,
                     u16_t size,
                     err_t err);

#define TCP_EVENT_ACCEPT(pcb, err, ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb), \
                                                             LWIP_EVENT_ACCEPT, NULL, 0, err)
#define TCP_EVENT_SENT(pcb, space, ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb), \
                                                             LWIP_EVENT_SENT, NULL, space, ERR_OK)
#define TCP_EVENT_RECV(pcb, p, err, ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb), \
                                                              LWIP_EVENT_RECV, (p), 0, (err))
#define TCP_EVENT_CONNECTED(pcb, err, ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb), \
                                                                LWIP_EVENT_CONNECTED, NULL, 0, (err))
#define TCP_EVENT_POLL(pcb, ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb), \
                                                      LWIP_EVENT_POLL, NULL, 0, ERR_OK)
#define TCP_EVENT_ERR(errf, arg, err) lwip_tcp_event((arg), NULL, \
                                                     LWIP_EVENT_ERR, NULL, 0, (err))
#else /* LWIP_EVENT_API */
#define TCP_EVENT_ACCEPT(pcb, err, ret) \
    if ((pcb)->accept != NULL)          \
    (ret = (pcb)->accept((pcb)->callback_arg, (pcb), (err)))
#define TCP_EVENT_SENT(pcb, space, ret) \
    if ((pcb)->sent != NULL)            \
    (ret = (pcb)->sent((pcb)->callback_arg, (pcb), (space)))
#define TCP_EVENT_RECV(pcb, p, err, ret)                           \
    if ((pcb)->recv != NULL) {                                     \
        ret = (pcb)->recv((pcb)->callback_arg, (pcb), (p), (err)); \
    } else {                                                       \
        pbuf_free(p);                                              \
    }
#define TCP_EVENT_CONNECTED(pcb, err, ret) \
    if ((pcb)->connected != NULL)          \
    (ret = (pcb)->connected((pcb)->callback_arg, (pcb), (err)))
#define TCP_EVENT_POLL(pcb, ret) \
    if ((pcb)->poll != NULL)     \
    (ret = (pcb)->poll((pcb)->callback_arg, (pcb)))
#define TCP_EVENT_ERR(errf, arg, err) \
    if ((errf) != NULL)               \
    (errf)((arg), (err))
#endif /* LWIP_EVENT_API */

/* This structure is used to repressent TCP segments when queued. */
struct tcp_seg
{
    struct tcp_seg *next;   /* used when putting segements on a queue */
    struct pbuf *p;         /* buffer containing data + TCP header */
    void *dataptr;          /* pointer to the TCP data in the pbuf */
    u16_t len;              /* the TCP length of this segment */
    struct tcp_hdr *tcphdr; /* the TCP header */
};

/* Internal functions and global variables: */
struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
void tcp_pcb_purge(struct tcp_pcb *pcb);
void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);

u8_t tcp_segs_free(struct tcp_seg *seg);
u8_t tcp_seg_free(struct tcp_seg *seg);
struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);

#define tcp_ack(pcb)                   \
    if ((pcb)->flags & TF_ACK_DELAY) { \
        (pcb)->flags &= ~TF_ACK_DELAY; \
        (pcb)->flags |= TF_ACK_NOW;    \
        tcp_output(pcb);               \
    } else {                           \
        (pcb)->flags |= TF_ACK_DELAY;  \
    }

#define tcp_ack_now(pcb)        \
    (pcb)->flags |= TF_ACK_NOW; \
    tcp_output(pcb)

err_t tcp_send_ctrl(struct tcp_pcb *pcb, u8_t flags);
err_t tcp_enqueue(struct tcp_pcb *pcb, void *dataptr, u16_t len,
                  u8_t flags, u8_t copy,
                  u8_t *optdata, u8_t optlen);

void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);

void tcp_rst(u32_t seqno, u32_t ackno,
             struct ip_addr *local_ip, struct ip_addr *remote_ip,
             u16_t local_port, u16_t remote_port);

u32_t tcp_next_iss(void);

void tcp_keepalive(struct tcp_pcb *pcb);

extern struct tcp_pcb *tcp_input_pcb;
extern u32_t tcp_ticks;

#if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
void tcp_debug_print(struct tcp_hdr *tcphdr);
void tcp_debug_print_flags(u8_t flags);
void tcp_debug_print_state(enum tcp_state s);
void tcp_debug_print_pcbs(void);
int tcp_pcbs_sane(void);
#else
#define tcp_debug_print(tcphdr)
#define tcp_debug_print_flags(flags)
#define tcp_debug_print_state(s)
#define tcp_debug_print_pcbs()
#define tcp_pcbs_sane() 1
#endif /* TCP_DEBUG */

#if NO_SYS
#define tcp_timer_needed()
#else
void tcp_timer_needed(void);
#endif

/* The TCP PCB lists. */
extern struct tcp_pcb_listen *tcp_listen_pcbs; /* List of all TCP PCBs in LISTEN state. */
extern struct tcp_pcb *tcp_active_pcbs;        /* List of all TCP PCBs that are in a
              state in which they accept or send
              data. */
extern struct tcp_pcb *tcp_tw_pcbs;            /* List of all TCP PCBs in TIME-WAIT. */

extern struct tcp_pcb *tcp_tmp_pcb; /* Only used for temporary storage. */

/* Axioms about the above lists:
   1) Every TCP PCB that is not CLOSED is in one of the lists.
   2) A PCB is only in one of the lists.
   3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
   4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
*/

/* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
   with a PCB list or removes a PCB from a list, respectively. */

#define TCP_REG(pcbs, npcb) \
    do {                    \
        npcb->next = *pcbs; \
        *(pcbs) = npcb;     \
        tcp_timer_needed(); \
    } while (0)
#define TCP_RMV(pcbs, npcb)                                                                   \
    do {                                                                                      \
        if (*(pcbs) == npcb) {                                                                \
            (*(pcbs)) = (*pcbs)->next;                                                        \
        } else                                                                                \
            for (tcp_tmp_pcb = *pcbs; tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
                if (tcp_tmp_pcb->next != NULL && tcp_tmp_pcb->next == npcb) {                 \
                    tcp_tmp_pcb->next = npcb->next;                                           \
                    break;                                                                    \
                }                                                                             \
            }                                                                                 \
        npcb->next = NULL;                                                                    \
    } while (0)
#endif /* __LWIP_TCP_H__ */
